Sensor sizes are expressed in inches notation because at the time of the popularization of digital image sensors they were used to replace video camera tubes. The common 1" circular video camera tubes have a rectangular photo sensitive area about 16 mm diagonal, so a digital sensor with a 16 mm diagonal size is a 1" video tube equivalent. The name of a 1" digital sensor should more accurately be read as "one inch video camera tube equivalent" sensor. Current digital image sensor size descriptors are the video camera tube equivalency size, not the actual size of the sensor. For example, a 1" sensor has a diagonal measurement of 16 mm.[26][27]

Sizes are often expressed as a fraction of an inch, with a one in the numerator, and a decimal number in the denominator. For example, 1/2.5 converts to 2/5 as a simple fraction, or 0.4 as a decimal number. This "inch" system brings a result approximately 1.5 times the length of the diagonal of the sensor. This "optical format" measure goes back to the way image sizes of video cameras used until the late 1980s were expressed, referring to the outside diameter of the glass envelope of the video camera tube. David Pogue of The New York Times states that "the actual sensor size is much smaller than what the camera companies publish – about one-third smaller." For example, a camera advertising a 1/2.7" sensor does not have a sensor with a diagonal of 0.37"; instead, the diagonal is closer to 0.26".[28][29][30] Instead of "formats", these sensor sizes are often called types, as in "1/2-inch-type CCD."

Due to inch-based sensor formats being not standardized, their exact dimensions may vary, but those listed are typical.[29] The listed sensor areas span more than a factor of 1000 and are proportional to the maximum possible collection of light and image resolution (same lens speed, i.e., minimum F-number), but in practice are not directly proportional to image noise or resolution due to other limitations. See comparisons.[31][32] Film format sizes are included for comparison. The following comparison is with respect to the aspect ratio of 4:3. The application examples of phone or camera may not show the exact sensor sizes.

Type  Diagonal (mm) Width (mm) Height (mm) Aspect Ratio Area (mm²) Stops (area)[33] Crop factor[
1 2 3 4 5 6 7 8
Type Diagonal (mm) Width (mm) Height (mm) Aspect Ratio Area (mm²) Stops (area)[33] Crop factor[34]
1/10" 1.60 1.28 0.96 4:3 1.23 -9.46 27.04
1/8" 2.00 1.60 1.20 4:3 1.92 -8.81 21.65
1/6" (Panasonic SDR-H20, SDR-H200) 3.00 2.40 1.80 4:3 4.32 -7.64 14.14
1/4"[35] 4.50 3.60 2.70 4:3 9.72 -6.47 10.81
1/3.6" (Nokia Lumia 720)[36] 5.00 4.00 3.00 4:3 12.0 -6.17 8.65
1/3.2" (iPhone 5)[37] 5.68 4.54 3.42 4:3 15.50 -5.80 7.61
1/3.09" Sony EXMOR IMX351[38] 5.82 4.66 3.5 4:3 16.3 -5.73 7.43
Standard 8 mm film frame 5.94 4.8 3.5 11:8 16.8 -5.68 7.28
1/3" (iPhone 5S, iPhone 6, LG G3[39]) 6.00 4.80 3.60 4:3 17.30 -5.64 7.21
1/2.9" Sony EXMOR IMX322[40] 6.23 4.98 3.74 4:3 18.63 -5.54 6.92
1/2.7" 6.72 5.37 4.04 4:3 21.70 -5.32 6.44
Super 8 mm film frame 7.04 5.79 4.01 13:9 23.22 -5.22 6.15
1/2.5" (Nokia Lumia 1520, Sony Cyber-shot DSC-T5, iPhone XS[41]) 7.18 5.76 4.29 4:3 24.70 -5.13 6.02
1/2.3" (Pentax Q, Sony Cyber-shot DSC-W330, GoPro HERO3, Panasonic HX-A500, Google Pixel/Pixel+, DJI Phantom 3[42]/Mavic 2 Zoom[43]), Nikon P1000/P900 7.66 6.17 4.55 4:3 28.50 -4.94 5.64
1/2.3" Sony Exmor IMX220[44] 7.87 6.30 4.72 4:3 29.73 -4.86 5.49
1/2" (Fujifilm HS30EXR, Xiaomi Mi 9, OnePlus 7, Espros EPC 660, DJI Mavic Air 2) 8.00 6.40 4.80 4:3 30.70 -4.81 5.41
1/1.8" (Nokia N8) (Olympus C-5050, C-5060, C-7070) 8.93 7.18 5.32 4:3 38.20 -4.50 4.84
1/1.7" (Pentax Q7, Canon G10, G15, Huawei P20 Pro, Huawei P30 Pro, Huawei Mate 20 Pro) 9.50 7.60 5.70 4:3 43.30 -4.32 4.55
1/1.6" (Fujifilm f200exr [2]) 10.07 8.08 6.01 4:3 48.56 -4.15 4.30
2/3" (Nokia Lumia 1020, Fujifilm X-S1, X20, XF1) 11.00 8.80 6.60 4:3 58.10 -3.89 3.93
1/1.33" (Samsung Galaxy S20 Ultra)[45] 12 9.6 7.2 4:3 69.12 -3.64 3.58
Standard 16 mm film frame 12.70 10.26 7.49 11:8 76.85 -3.49 3.41
1/1.2" (Nokia 808 PureView) 13.33 10.67 8.00 4:3 85.33 -3.34 3.24
Blackmagic Pocket Cinema Camera & Blackmagic Studio Camera 14.32 12.48 7.02 16:9 87.6 -3.30 3.02
Super 16 mm film frame 14.54 12.52 7.41 5:3 92.80 -3.22 2.97
1" Nikon CX, Sony RX100 and RX10, Samsung NX Mini 15.86 13.20 8.80 3:2 116 -2.89 2.72
1" Digital Bolex d16 16.00 12.80 9.60 4:3 123 -2.81 2.70
1.1" Sony IMX253[46] 17.46 14.10 10.30 11:8 145 -2.57 2.47
Blackmagic Cinema Camera EF 18.13 15.81 8.88 16:9 140 -2.62 2.38
Blackmagic Pocket Cinema Camera 4K 21.44 18.96 10 19:10 190 -2.19 2.01
Four Thirds, Micro Four Thirds ("4/3", "m4/3") 21.60 17.30 13 4:3 225 -1.94 2.00
Blackmagic Production Camera/URSA/URSA Mini 4K 24.23 21.12 11.88 16:9 251 -1.78 1.79
1.5" Canon PowerShot G1 X Mark II 23.36 18.70 14 4:3 262 -1.72 1.85
"35mm" 2 Perf Techniscope 23.85 21.95 9.35 7:3 205.23 -2.07 1.81
original Sigma Foveon X3 24.90 20.70 13.80 3:2 286 -1.60 1.74
RED DRAGON 4.5K (RAVEN) 25.50 23.00 10.80 19:9 248.4 -1.80 1.66
"Super 35mm" 2 Perf 26.58 24.89 9.35 8:3 232.7 -1.89 1.62
Canon EF-S, APS-C 26.82 22.30 14.90 3:2 332 -1.38 1.61
Standard 35 mm film frame (movie) 27.20 22.0 16.0 11:8 352 -1.30 1.59
Blackmagic URSA Mini/Pro 4.6K 29 25.34 14.25 16:9 361 -1.26 1.49
APS-C (Sony α, Sony E, Nikon DX, Pentax K, Samsung NX, Fuji X) 28.2–28.4 23.6–23.7 15.60 3:2 368–370 -1.23 to -1.22 1.52–1.54
Super 35 mm film 3 perf 28.48 24.89 13.86 9:5 344.97 -1.32 1.51
RED DRAGON 5K S35 28.9 25.6 13.5 17:9 345.6 -1.32 1.49
Super 35mm film 4 perf 31.11 24.89 18.66 4:3 464 -0.90 1.39
Canon APS-H 33.50 27.90 18.60 3:2 519 -0.74 1.29
ARRI ALEV III (ALEXA SXT, ALEXA MINI, AMIRA), RED HELIUM 8K S35 33.80 29.90 15.77 17:9 471.52 -0.87 1.28
RED DRAGON 6K S35 34.50 30.7 15.8 35:18 485.06 -0.83 1.25
35 mm film full-frame, (Canon EF, Nikon FX, Pentax K-1, Sony α, Sony FE, Leica M) 43.1–43.3 35.8–36 23.9–24 3:2 856–864 0 1.0
ARRI ALEXA LF 44.71 36.70 25.54 13:9 937.32 +0.12 0.96
RED MONSTRO 8K 46.31 40.96 21.60 17:9 884.74 +0.03 0.93
Leica S 54 45 30 3:2 1350 +0.64 0.80
Pentax 645D, Hasselblad X1D-50c, CFV-50c, Fuji GFX 50S 55 44 33 4:3 1452 +0.75 0.78
Standard 65 mm film frame 57.30 52.48 23.01 7:3 1208 +0.48 0.76
ARRI ALEXA 65 59.86 54.12 25.58 19:9 1384.39 +0.68 0.72
Kodak KAF 39000 CCD[47] 61.30 49 36.80 4:3 1803 +1.06 0.71
Leaf AFi 10 66.57 56 36 14:9 2016 +1.22 0.65
Medium-format (Hasselblad H5D-60)[48] 67.08 53.7 40.2 4:3 2159 +1.32 0.65
Phase One P 65+, IQ160, IQ180 67.40 53.90 40.40 4:3 2178 +1.33 0.64
Medium-format 6×4.5 cm (also called 645 format) 70 42 56 3:4 2352 +1.44 0.614
Medium-format 6×6 cm 79 56 56 1:1 3136 +1.86 0.538
IMAX film frame 87.91 70.41 52.63 4:3 3706 +2.10 0.49
Medium-format 6×7 cm 89.6 70 56 5:4 3920 +2.18 0.469
Medium-format 6×8 cm 94.4 76 56 3:4 4256 +2.30 0.458
Medium-format 6×9 cm 101 84 56 3:2 4704 +2.44 0.43
Large-format film 4×5 inch 150 121 97 5:4 11737 +3.76 0.29
Large-format film 5×7 inch 210 178 127 7:5 22606 +4.71 0.238
Large-format film 8×10 inch 300 254 203 5:4 51562 +5.90 0.143